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CHANGING MEASLES IMMUNIZATION SCHEDULE: THE SAUDI EXPERIENCE

Al-Ghamdi S.Y.

Al-Gassem Regional Health Affairs

Objective: Schwartz measles vaccine was introduced to Saudi Arabia since 1974 but only in 1982, measles at the age of 9 months, became a requirement of obtaining health certificate and coverage rate increased to 90%. The aim of this paper is to evaluate the effect of this intervention on the disease pattern and to evaluate different immunization response to this change in pattern

Methods: Review study of immune response to measles vaccine in Saudi Arabia in different stages of vaccine introduction and the effect on epidemiological pattern.

Results: The introduction of Schwartz measles vaccine was accompanied by remarkable decrease in disease incidence but on 1990 immunogenicity study showed that 33% and 36% of Saudi infants were susceptible to disease at 6 and 9 months respectively and even vaccinated children showed only 65% seroconversion. Immunogenicity studies in 1990 showed that Edmonston-Zagreb (E-Z) measles vaccine can seroconvert 95% of Saudi Infants at 6 months of age. Accordingly measles immunization schedule was changed to two-dose schedule including E-Z monovaccine at 6 months and MMR at 12 months. The impact of this change will be presented and the rational of conducting MMR campaign for school children on 1999-2000 will be discussed.

Conclusion: Measles immunization is an intervention in measles ecology, which needs continuous assessment and policy modification until disease eradication is achieved.